1. Field of the Invention
The present invention relates to a D.C. motor and a winding method for coils of the D.C. motor, wherein the stator coils of the motor can be conveniently wound to thereby construct a stator of a D.C. motor.
2. Description of the Related Art
FIG. 7 of the drawings illustrates a conventional D.C. motor stator 90 formed by a radial winding method. In the winding method for the stator 90, an end of a conducting wire 901 forms a first connection V1 before the winding procedure. When the conducting wire 901 has been wound around a half number of the pole arms, i.e., pole arms 90a and 90b of the stator 90, the winding procedure is halted for pulling out the conducting wire 901 to form a second connection V0 (the common connection). Then, the winding procedure continues for the remaining of the pole arms (i.e., pole arms 90c and 90d). After the winding procedure is finished, the other end of the conducting wire 901 forms a third connection V2. The stator 90 may use a dual-coil motor driver to generate alternating rotational magnetic fields to thereby drive the rotor having magnetic poles N and S. Nevertheless, the winding procedure must be interrupted for formation of the second connection V0.
FIG. 8 illustrates a stator 91 using another conventional radial winding method. An end of a conducting wire 911 forms a first connection V1 before winding around the stator 91. After the winding procedure is finished, the other end of the conducting wire 911 forms a second connection V2. The stator 91 may use a single-coil motor driver and supplies the single coil with alternating electric current to generate alternating rotational magnetic fields to thereby drive the rotor having magnetic poles N and S. Nevertheless, in this method using a single conducting wire 911 for carrying out winding, the conducting wire 911 must be wound around each pole arm 91a, 91b, 91c, 91d for as many turns as the required turns of the coil. The winding time for the stator 91 cannot be reduced, as the winding speed is limited.
Another previously proposed D.C. motor, as illustrated in FIG. 9 of the drawings of the present application, comprises a stator 92 having a number of pole arms 92a, 92b, 92c, and 92d around which two conductive wires are wound. Each conducting wire 921, 922 needs to be wound for just a half of turns to finish winding of the stator 92 with required turns. After formation of the winding on the stator 92, it can then be decided the number (two or three) of the connections to be connected with the drive circuit.
Each conducting wire of each of these brushless motors having a radial winding and a radial air gap is wound around each pole arm of the stator. The winding procedure is difficult and the winding speed is largely limited, as the gap between the pole arms is small. In addition, an insulating layer deposited on an outer periphery of the conducting wire tends to be damaged by the pole arms during the winding procedure, which results in a short circuit of the coils.
FIG. 10 of the drawings, which corresponds to FIG. 4 of U.S. Pat. No. 4,922,162 to Shiraki et al. issued on May 1, 1990 and entitled ISK-TYPE SINGLE-PHASE BRSHELESS MOTOR, discloses a stator for a brushless motor having an axial gap. The coils 931 and 932 are firstly wound for the required turns and then bonded by tapes or bonding agents to the stator yokes 93a and 93b on a circuit board 93. Each coil 931, 932 has terminals 931a and 93lb, 932a and 932b passing through V-shaped notches in the circuit board 93. The terminal 931a, 931b, 932a, 932b are soldered to a printed conductor pattern formed on a lower face of the printed circuit board 20 so as to establish electric connection therebetween. The coils of such a conventional brushless motor having an axial air gap require careful soldering so as to avoid wrong connection although they can be wound easily.
It is an object of the present invention to provide a method for carrying out winding of a D.C. motor in which winding of the stator coils can be easily achieved and damage to the coils by the pole plates of the stator during the winding procedure can be avoided.
It is another object of the present invention to provide a D.C brushless motor having stator coils that can be easily fixed for easy processing and assembly.
A winding method in accordance with the present invention comprises winding a single conducting wire around a predetermined number of pegs in sequence to thereby form a stator coil assembly having even coils and two ends. The winding direction of each coil is opposite to a coil adjacent thereto. The stator coil assembly having even coils is mounted to a casing of a D.C. motor with the coils located corresponding to a permanent magnet of a rotor. The rotor having the permanent magnet is driven to turn by magnetic forces created as a result of energizing the coils.
Other objects, specific advantages, and novel features of the invention will become more apparent from the following detailed description and preferable embodiments when taken in conjunction with the accompanying drawings.